A touch panel is a device for detecting a position of an object or a finger while the object or finger is touched on a point of the screen of a display device.
FIG. 1 is a cross sectional view showing a conventional liquid crystal display apparatus.
Referring to FIG. 1, the liquid crystal display apparatus includes a liquid crystal display panel 20 for displaying an image and a touch panel for detecting a position of an object that touches an outer surface of the touch panel.
The liquid crystal display panel 20 includes a thin film transistor (TFT) substrate 21, a color filter (C/F) substrate 23 and a liquid crystal layer 25 interposed between the TFT substrate 21 and the color filter substrate 23. A pixel electrode 22 is formed on an upper surface of the TFT substrate. The color filter substrate 23 faces the TFT substrate 21, and a common electrode 24 is formed on a lower surface of the color filter substrate.
A first polarizer 26 is formed on a lower surface of the TFT substrate 21, and a second polarizer 27 is formed on an upper surface of the color filter substrate 23.
The touch panel 30 includes a first substrate 31, a second substrate 34, a first transparent electrode 32 and a second transparent electrode 35. The second substrate is spaced apart from the first substrate by a predetermined distance. The first transparent electrode 32 is formed on an upper surface of the first substrate 31, and the second transparent electrodes 35 is formed on a lower surface of the second substrate 34. The upper surface of the first substrate 31 is opposite to the lower surface of the second substrate 34.
The first substrate 31 is comprised of a transparent material so that the light from the liquid crystal display panel may be transmitted through the first substrate 31. The second substrate 34 is comprised of an optical film having an isotropic refractivity.
The entire thickness of the liquid crystal display apparatus 10 is increased due to two substrates such as the color filter substrate 23 and the first substrate 31 disposed on both surfaces of the second polarizer 27.
In addition, loss of light is increased since the light incident into the liquid crystal display panel 20 and the light exiting from the liquid crystal display panel 20 pass through both color filter substrate 23 and first substrate 31.